Ensure safe resource cleanup when replacing SSTables

Patch by belliotsmith; reviewed by Tyler Hobbs for CASSANDRA-6912
Make sure we clear out all levels when rebuilding leveled manifest.

Patch by jbellis; reviewed by marcuse for CASSANDRA-6957
Don't shut MessagingService down.

Patch by brandonwilliams, reviewed by Benedict for CASSANDRA-6948
Merge branch 'cassandra-2.0' into cassandra-2.1
Avoid build failure due to ANTLR timeout

Patch by Ben Chan; reviewed by Tyler Hobbs for CASSANDRA-6991
Merge branch 'cassandra-2.0' into cassandra-2.1
Fix NPE caused by CASSANDRA-6818

patch by yukim; reviewed by thobbs for CASSANDRA-6984
Merge branch 'cassandra-2.0' into cassandra-2.1
Schedule schema pull in onChange.

Patch by brandonwilliams, reviewed by Russ Hatch for CASSANDRA-6971
Merge branch 'cassandra-1.2' into cassandra-2.0
Merge branch 'cassandra-2.0' into cassandra-2.1
fix broken build
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	src/java/org/apache/cassandra/service/StorageService.java
Merge branch 'cassandra-2.0' into cassandra-2.1
Fix concurrency issue for CASSANDRA-6818

patch by yukim; reviewed by thobbs for CASSANDRA-7007
Merge branch 'cassandra-2.0' into cassandra-2.1
Put nodes into hibernate when join_ring is false.

Patch by brandonwilliams, reviewed by Tyler Hobbs for CASSANDRA-6961
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	src/java/org/apache/cassandra/service/StorageService.java
Update changes
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt